1. Field of the Invention
The present invention generally relates to a display device or a panel, and in particular, to a flat panel display (FPD) or a flat panel with touch-sensing function (touch panel).
2. Description of Related Art
To meet the requirements of a modem product on high speed, high efficiency and compact design, all kinds of electronic components attempt to be developed towards miniaturization. Various portable electronic devices, such as notebooks, mobile phones, electronic dictionaries, personal digital assistants (PDAs), web pads, and tablet PCs have become the mainstream. In an image displays of portable electronic devices, flat panel displays have been widely used due to advantages of high space utilization, high display quality, low power consumption and no radiation, specifically, liquid crystal displays (LCDs) are preferred and widely used.
In general, an LCD comprises an LCD panel and a plurality of driver IC (integrated circuit) chips and other electrical components. The driver IC chips or electrical component are disposed on a glass substrate or a circuit board in many ways. The circuit board with the driver IC chips or the electrical components are disposed at the bottom of the LCD panel and electrically connected to the LCD panel through a flexible printed circuit (FPC). In addition, the driver IC chips or electrical components can be also disposed on a control circuit board in a portable electronic device, wherein the driver IC chips or the electrical components are also electrically connected to the LCD panel through an FPC. The driver IC chips usually mean IC chips used to drive thin film transistors of the LCD panel. In contrast, the electrical components are IC chips, some of which are used to drive a touch panel.
Along with the progress of display technology, an LCD panel in some applications is required to be synchronized with the operations to turn on and turn off a light source for providing a better display effect. To meet the demand of a user, other elements in an LCD are also required to be synchronized for operations with the displaying of the LCD panel, and therefore, the signals of the other elements in the LCD are conducted or processed by another FPC. The above-mentioned other elements includes, for example, a circuit to turn on and turn off the light source in the backlight module or a processing circuit in a touch panel to judge a touching position. Consequently, how to integrate a plurality of FPCs in a flat panel display to meet the requirements of consumers is an important project.
FIG. 1 is a diagram of a conventional LCD. Referring to FIG. 1, an LCD 100 includes an LCD panel 110, a first flexible printed circuit 120 and a second flexible printed circuit 130. The second flexible printed circuit 130 is usually used for controlling the display signals of the LCD panel 110, and the first flexible printed circuit 120 is usually used for controlling the operation signals of other elements, for example, control signal of a backlight module or touching-sensing signal of a touch panel. As shown in FIG. 1, the second flexible printed circuit 130 has a plurality of pads 122 arranged side by side, and the first flexible printed circuit 120 also has a plurality of pins 132 arranged side by side. Each of the pins 132 on the first flexible printed circuit 120 is respectively connected to a corresponding pad 122 on the second flexible printed circuit 130 so as to form a plurality of electrical connections 140 arranged side by side, as shown in FIG. 1.
In order to meet the requirements of consumers on the high resolution, the high response speed, the high contrast ratio of LCDs, and the function of the touch panel, the number of the electrical connections 140 between the second flexible printed circuit 130 and the first flexible printed circuit 120 is increased, so that the bonding area between the pins 132 and the pads 122 is not enough. In other words, if the bonding area keeps unchanged, the gap between every two adjacent electrical connections 140 must be decreased to meet the requirements of the high resolution, the high response speed, the high contrast, and the function of the touch panel, which likely makes two adjacent electrical connections 140 to be mutually bridged and short-circuited during soldering the pins 132 and the pads 122. As a result, the production yield of the LCD 100 is reduced.